Darwin has done, in showing that for the future the phenomena of plant movement can and indeed must be studied from a single point of view."
The work was begun in the summer of 1877, after the publication of 'Different Forms of Flowers,' and by the autumn his enthusiasm for the subject was thoroughly established, and he wrote to Mr. Dyer: "I am all on fire at the work." At this time he was studying the movements of cotyledons, in which the sleep of plants is to be observed in its simplest form; in the following spring he was trying to discover what useful purpose these sleep-movements could serve, and wrote to Sir Joseph Hooker (March 25th, 1878):--
"I think we have PROVED that the sleep of plants is to lessen the injury to the leaves from radiation. This has interested me much, and has cost us great labour, as it has been a problem since the time of Linnaeus. But we have killed or badly injured a multitude of plants: N.B.--Oxalis carnosa was most valuable, but last night was killed."
His letters of this period do not give any connected account of the progress of the work. The two following are given as being characteristic of the author:]
CHARLES DARWIN TO W. THISELTON DYER. Down, June 2, 1878.
My dear Dyer,
I remember saying that I should die a disgraced man if I did not observe a seedling Cactus and Cycas, and you have saved me from this horrible fate, as they move splendidly and normally. But I have two questions to ask: the Cycas observed was a huge seed in a broad and very shallow pot with cocoa-nut fibre as I suppose. It was named only Cycas. Was it Cycas pectinata? I suppose that I cannot be wrong in believing that what first appears above ground is a true leaf, for I can see no stem or axis. Lastly, you may remember that I said that we could not raise Opuntia nigricans; now I must confess to a piece of stupidity; one did come up, but my gardener and self stared at it, and concluded that it could not be a seedling Opuntia, but now that I have seen one of O. basilaris, I am sure it was; I observed it only casually, and saw movements, which makes me wish to observe carefully another. If you have any fruit, will Mr. Lynch (Mr. R.I. Lynch, now Curator of the Botanic Garden at Cambridge was at this time in the Royal Gardens, Kew.) be so kind as to send one more?
I am working away like a slave at radicles [roots] and at movements of true leaves, for I have pretty well done with cotyledons...
That was an EXCELLENT letter about the Gardens (This refers to an attempt to induce the Government to open the Royal Gardens at Kew in the morning.): I had hoped that the agitation was over. Politicians are a poor truckling lot, for [they] must see the wretched effects of keeping the gardens open all day long.
Your ever troublesome friend, CH. DARWIN.
CHARLES DARWIN TO W. THISELTON DYER. 4 Bryanston St., Portman Square, November 21 [1878].
My dear Dyer,
I must thank you for all the wonderful trouble which you have taken about the seeds of Impatiens, and on scores of other occasions. It in truth makes me feel ashamed of myself, and I cannot help thinking: "Oh Lord, when he sees our book he will cry out, is this all for which I have helped so much!" In seriousness, I hope that we have made out some points, but I fear that we have done very little for the labour which we have expended on our work. We are here for a week for a little rest, which I needed.
If I remember right, November 30th, is the anniversary at the Royal, and I fear Sir Joseph must be almost at the last gasp. I shall be glad when he is no longer President.
Yours very sincerely, CH. DARWIN.
[In the spring of the following year, 1879. When he was engaged in putting his results together, he wrote somewhat despondingly to Mr. Dyer: "I am overwhelmed with my notes, and almost too old to undertake the job which I have in hand--i.e. movements of all kinds. Yet it is worse to be idle."
Later on in the year, when the work was approaching completion, he wrote to Prof.